Selection of the Optimal Puncture Needle for Induction of a Rat Intervertebral Disc Degeneration Model

Background: The incidence of intervertebral disc (IVD) degeneration has increased in recent years. A simple, reliable, and reproducible animal model is critical for understanding the underlying mechanisms of IVD degeneration. The caudal discs of rats have been proposed as a common puncture model in which to induce IVD degeneration. However, there is still no consensus on the size of needle to be used. Objectives: The present study aimed to identify the appropriate needle size to establish an IVD degeneration model. Study Design: A randomized, experimental trial. Setting: Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, China. Methods: Validity was verified by magnetic resonance imaging (MRI) and histology. Results: From T2-weighted MRI imaging and histological examination, the IVD punctured by the 16-gauge needle degenerated acutely one week after the operation, whereas the 26-gauge needle puncture did no harm to the IVD. An 18-gauge needle showed a progressive degeneration in IVD. Limitations: The observation period was not very long (4 weeks). Conclusions: An 18-gauge needle can be used to induce IVD degeneration in rats. Therefore, an 18-gauge needle is the optimal selection to establish the degenerative IVD model on rats, whereas the 26-gauge needle failed to cause IVD degeneration. Thus, to study the prevention and treatment of IVD degeneration, a 26-gauge needle can be used for IVD injection of growth factors, plasmids, and drugs. A 16-gauge needle may be used to induce acute disc injury, but not IVD degeneration. Key words: Low back pain, degenerative intervertebral disc, animal model, puncture needle, rat model, optimal choice